This invention concerns cell-mediated immunity. A typical manifestation of cell-mediated immunity is the delayed hypersensitivity ("DH") skin reaction. A DH skin reaction is observed when an appropriate antigen is injected subcutaneously. Within 24 to 48 hours, local inflammation (erythema) and a swelling and thickening (induration) are observed in a sensitive individual. The degree of sensitivity may be measured by the size and severity of the reaction. The DH reaction also presents characteristic histological findings--specifically, perivascular infiltration of lymphocytes and monocytes in the inflamed area. The cells seen at the site of a DH reaction are derived from the peripheral blood leukocyte (PBL) population.
The mechanisms of cell-mediated immunity are as yet incompletely understood. It is known that the cells which mediate the response are capable of responding in a variety of ways to a challenge from an antigen. These responses include: proliferation of cells bearing specific sensitivity to a given antigen; the induction and multiplication of cells mediating a variety of immune functions, including antibody production; and reactions against foreign cells (such as pathogens or transplants) and tumors.
The present invention relates to the discovery of (1) a method for extracting a "suppressor" of the immunity system, which is isolated from dialyzed extracts of leukocytes, and (2) the suppressor itself that is so extracted. This suppressor profoundly affects the quality and quantity of cell-mediated immunity responses; is useful in the treatment of a variety of clinical conditions characterized by excessive or undesired reaction to a specific cell or antigen; and is useful in the alleviation of certain allergic conditions.
The term "suppressor," and much of the background relevant to the U.S. Pat. No. 4,468,379, Aug. 28, 1984. The prior art in this field is also discussed in the said '379 patent. That discussion is incorporated herein by reference. For the present purpose, the term suppressor may be considered to mean a substance that when administered to a human or other mammalian subject causes a nonspecific (i.e., not antigen-dependent) lessening of the magnitude or rate of immune system reaction, for example as measured by DH response.